With his current goal now to increase Qi Purity as much as possible, Arthur went ahead and converted qi into Inferior Spirit Slag nonstop. However, that did not mean that he actually did convert qi without taking any breaks.

As he did not know the entire Fibonacci sequence, Arthur decided to stop converting whenever he met the necessary amount of Inferior Spirit Slag to exchange for the amount of System Points he would need to upgrade. Sure, calculating the next step of the Fibonacci sequence might be simple as the next term was just the sum of the previous two terms, but Arthur did not even bother thinking about it. Perhaps some other time when he had better mental acuity.

And with that, Arthur went through the various terms of the Fibonacci sequence, taking at least slightly over 4 days to increase Qi Purity from Tier 0, Grade 3 to Tier 0, Grade 8. Thanks to that, the amount of Inferior Spirit Slag that he would produce per point of qi had more or less doubled, jumping from 40 grams per batch to 90 grams per batch.

Of course, with the range and duration of [Spirit Sense] being highly reliant on how high Qi Purity was, the skill was also improved. Currently, each point of qi now allowed him to create a field that spanned 450 meters, lasting for 45 minutes before disappearing. He was certain that it wouldn’t be long until he would have [Spirit Sense] constantly active, just like how [Spirit Aura] was also constantly active.

Speaking of [Spirit Aura], with how the boost in qi density was related to Qi Purity, that part had also improved, increasing from 5% to 11.25%. At this point, he was sure that once a person entered the range of the skill’s domain, they would quickly feel that there was more qi in the air than usual. Though, it was quite unfortunate that this domain only spanned about three meters.

Then again, he was not really dismayed by the fact that his domain only spanned that small. After all, with him continuously producing Inferior Spirit Slag, a decently huge pile of the stuff had finally appeared above where he was, weighing around 8 kilograms at the very least.

Though, that did not mean that he would stop producing Inferior Spirit Slag now that he had reached Tier 0, Grade 8. Well, he would stop focusing on Qi Purity eventually, but that was only after he had reached Tier 0, Grade 9, the final grade before he would reach Tier 1 Qi Purity.

At this point, his mental acuity had considerably improved, finally allowing him to get the knack behind the terms of the Fibonacci sequence. With that, he could not help but stare at the current cost of the upgrade for Qi Purity, wondering why it did not match up with what the next term of the sequence was.

Eventually, he thought that it would be better for him to ask Sisa about this. And soon, he did just that.

“Hey, Sisa. Mind telling me why the upgrade to Tier 0, Grade 9 costs 50 points and not 55?” Arthur asked, genuinely curious. Though, with his increased mental acuity, it was no surprise that he had already made a few hypotheses of his own.

“Well, according to the knowledge given to me by Theresa, there would eventually come a point where the progression of cost would stop following the Fibonacci sequence and instead follow an arbitrary value. In this case, the last grade of Qi Purity, which costs 50 instead of 55,” Sisa soon explained. “However, the cost for the next upgrade, which is the upgrade to Tier 1, Grade 0, is actually 100 points, double of the previous one.”

“Hmm…” As Arthur listened to her explanation, he pondered over it for a bit, getting the feeling that there was a pattern in there. Fortunately, he quickly found it out, asking Sisa, “So, that means the loop would start all over again for the next tier, but just at a multiplied factor?”

“Correct,” Sisa replied. “It seems the upgrade from Qi Purity is actually working its magic.”

“I do have to say I wouldn’t be able to figure it out if not for the upgrades.” Arthur chuckled in response. “However, if the upgrade to Tier 1, Grade 0 costs 100 points, then what would the upgrade to Tier 1, Grade 1 cost? If I remember correctly, the upgrade to Tier 0, Grade 1 cost 1 point. If we follow the natural progression, then wouldn’t the cost not line up?”

“Unfortunately, I cannot answer that question,” Sisa replied. “You’ll have to save up points and find that out for yourself, Arthur.”

“Sometimes I wonder if there’s a way for me to upgrade your answering capabilities,” Arthur could not help but say as he committed the information to memory before continuing to convert qi into Inferior Spirit Slag. With each activation now producing 90 grams of the stuff, it could be said that Arthur was saving quite a lot of time in upgrading Qi Purity to Tier 0, Grade 9.

Nevertheless, with the last upgrade costing 50 System Points, it still took quite a long while for him to amass enough Inferior Spirit Slag for exchange. In fact, it took him almost two whole days to do so, being left with 40 grams near the cube once more as 5 kilograms of Inferior Spirit Slag was sent to the pile, instantly making the pile about 50% bigger.

“And I thought I wouldn’t have any more excess after the upgrade to Tier 0, Grade 8,” Arthur could not help but mutter as he stared at the small pile of dust near the now light blue cube. Placing that thought at the back of his head, he then opened up the upgrade screen, commanding the system to upgrade Qi Purity to the peak of Tier 0 Qi Purity.

Ding!

Would you like to upgrade [Qi Purity]? This will cost 50 System Points.

As the prompt appeared this time around, he could not help but say with a light sigh, “To think that I’ve continuously converted qi into Inferior Spirit Slag for about a week now. No, wait. For over a week now.”

“Then again, I wouldn’t have gotten anywhere if not for [Qi Conversion].”

“Anyways, yes.”

Ding!

[Qi Purity] has been upgraded to Tier 0, Grade 9.

[Qi Conversion] now yields 100 grams of Inferior Spirit Slag.

[Spirit Sense] can now create a basic sensory field spanning 500 meters, lasting 50 minutes before disappearing.

[Spirit Aura] now boosts qi density within the domain by 12.5%.

Seeing the results of his labor laid out in front of him through the notifications, Arthur could not help but feel a sense of pride well up in him as he wondered what he should upgrade next. At this point, he had now found the process of conversion as something meditative.

“Hmm… I should probably upgrade Qi Capacity next.”

…

Under the rays of the hot sun, two figures could be seen walking across the plains, their backs more or less drenched in sweat.

One was a man in his late twenties, sporting a dark green robe that seemed to complement his amicable face. The other was a woman a few years older than the man, wearing a light gray robe as she exuded a somewhat mature charm.

“Qin, are you sure you want us to build our house here?” the man could not help but ask the woman.

“What’s wrong? Wouldn’t it be for the best if we settled here? After all, the land is flat and the view is amazing,” the woman named Qin replied.

“Well, sure. Settling down in this area would indeed be great in the long term. However, there’s no fertile land here,” the man said.

Although the main reason why the couple was traveling was due to the fact that they were looking for the perfect place where they could build their house and settle down, they also had to consider where they would get their food. Sure, they could hunt for food as there were quite a few animals in the area. However, a diet mainly composed of meat was something that neither of the two really wanted.

“Should we settle down near a river, then?” Qin asked the man. “Then again, you’re the farmer between the two of us, Jian. It’s your call.”

“Although it’s not wrong to say that we should settle near a body of water for farming, it’s not like it’s difficult to carry water from a faraway place,” Jian replied. “We’re already at the Essence Gathering Realm, after all. We should make full use of our strengths.”

He then continued, “What we really need is a way to make the land more fertile, allowing us to grow plants and vegetables easier. If we could get our hands on some sort of fertilizer, then our problems would be solved.”

“Is any kind of fertilizer fine? Or does it have to be something specific?” Qin could not help but ask soon after. At this moment, she knew that her husband was geeking out, so instead of stopping him, she instead urged him to think about it a bit more, fanning the flames.

“Well, it’s not like we have to get our hands on the best fertilizer there is. I’m pretty sure we could even make our own through composting,” he replied. “Though, I’ve heard that there’s a special type of fertilizer farmers use that makes plants and vegetables grow at least ten times faster.”

“Oh? Does fertilizer like that really exist?” Qin responded, her expression that of genuine shock.

“Yeah, it surprisingly does,” he said in response. “It’s called Spirit Slag. Most of the time it’s colored gray, with only the higher quality ones being white. In any case, the reason why it’s called Spirit Slag is because of the trace amounts of qi that it contains, naturally increasing the growth speed of plants.”

“Spirit Slag, huh?” Qin could not help but mutter, only to notice that a decently large pile of something gray could be seen about a dozen meters away from where they were. Wondering if that was it, she looked at Jian and pointed at it, asking, “Jian, isn’t that the Spirit Slag you were just talking about?”

“Hmm?” In response, Jian looked at the place where his wife was pointing, only for his eyes to widen in shock as he shouted not long after, “Almighty heavens, thank you for this blessing!”